1 /*
2 * proc_devtree.c - handles /proc/device-tree
3 *
4 * Copyright 1997 Paul Mackerras
5 */
6 #include <linux/errno.h>
7 #include <linux/sched.h>
8 #include <linux/proc_fs.h>
9 #include <linux/stat.h>
10 #include <linux/string.h>
11 #include <asm/prom.h>
12 #include <asm/uaccess.h>
13
14 static struct proc_dir_entry *proc_device_tree;
15
16 /*
17 * Supply data on a read from /proc/device-tree/node/property.
18 */
property_read_proc(char * page,char ** start,off_t off,int count,int * eof,void * data)19 static int property_read_proc(char *page, char **start, off_t off,
20 int count, int *eof, void *data)
21 {
22 struct property *pp = data;
23 int n;
24
25 if (off >= pp->length) {
26 *eof = 1;
27 return 0;
28 }
29 n = pp->length - off;
30 if (n > count)
31 n = count;
32 else
33 *eof = 1;
34 memcpy(page, pp->value + off, n);
35 *start = page;
36 return n;
37 }
38
39 /*
40 * For a node with a name like "gc@10", we make symlinks called "gc"
41 * and "@10" to it.
42 */
43
44 /*
45 * Process a node, adding entries for its children and its properties.
46 */
add_node(struct device_node * np,struct proc_dir_entry * de)47 static void add_node(struct device_node *np, struct proc_dir_entry *de)
48 {
49 struct property *pp;
50 struct proc_dir_entry *ent;
51 struct device_node *child, *sib;
52 const char *p, *at;
53 int l;
54 struct proc_dir_entry *list, **lastp, *al;
55
56 lastp = &list;
57 for (pp = np->properties; pp != 0; pp = pp->next) {
58 /*
59 * Unfortunately proc_register puts each new entry
60 * at the beginning of the list. So we rearrange them.
61 */
62 ent = create_proc_read_entry(pp->name, strncmp(pp->name, "security-", 9) ?
63 S_IRUGO : S_IRUSR, de, property_read_proc, pp);
64 if (ent == 0)
65 break;
66 if (!strncmp(pp->name, "security-", 9))
67 ent->size = 0; /* don't leak number of password chars */
68 else
69 ent->size = pp->length;
70 *lastp = ent;
71 lastp = &ent->next;
72 }
73 for (child = np->child; child != 0; child = child->sibling) {
74 p = strrchr(child->full_name, '/');
75 if (p == 0)
76 p = child->full_name;
77 else
78 ++p;
79 /* chop off '@0' if the name ends with that */
80 l = strlen(p);
81 if (l > 2 && p[l-2] == '@' && p[l-1] == '0')
82 l -= 2;
83 ent = proc_mkdir(p, de);
84 if (ent == 0)
85 break;
86 *lastp = ent;
87 lastp = &ent->next;
88 add_node(child, ent);
89
90 /*
91 * If we left the address part on the name, consider
92 * adding symlinks from the name and address parts.
93 */
94 if (p[l] != 0 || (at = strchr(p, '@')) == 0)
95 continue;
96
97 /*
98 * If this is the first node with a given name property,
99 * add a symlink with the name property as its name.
100 */
101 for (sib = np->child; sib != child; sib = sib->sibling)
102 if (sib->name && strcmp(sib->name, child->name) == 0)
103 break;
104 if (sib == child && strncmp(p, child->name, l) != 0) {
105 al = proc_symlink(child->name, de, ent->name);
106 if (al == 0)
107 break;
108 *lastp = al;
109 lastp = &al->next;
110 }
111
112 /*
113 * Add another directory with the @address part as its name.
114 */
115 al = proc_symlink(at, de, ent->name);
116 if (al == 0)
117 break;
118 *lastp = al;
119 lastp = &al->next;
120 }
121 *lastp = 0;
122 de->subdir = list;
123 }
124
125 /*
126 * Called on initialization to set up the /proc/device-tree subtree
127 */
proc_device_tree_init(void)128 void proc_device_tree_init(void)
129 {
130 struct device_node *root;
131 if ( !have_of )
132 return;
133 proc_device_tree = proc_mkdir("device-tree", 0);
134 if (proc_device_tree == 0)
135 return;
136 root = find_path_device("/");
137 if (root == 0) {
138 printk(KERN_ERR "/proc/device-tree: can't find root\n");
139 return;
140 }
141 add_node(root, proc_device_tree);
142 }
143